Rust is the enemy of any gun but old guns are affected more due to the inferior quality of iron used in the time these weapons were manufactured. Moreover, the fact that combustion residue of black powder is very aggressive ads to the vulnerability of corrosion to these guns. Take it for granted that 150 years ago poor gun maintenance was common practice too! We distinguish two types of corrosion: surface rust and deeply pitted rust. The first type is fairly easy to treat; the second form requires much heavier intervention.
There are some options to get rid of light rust:
  • Brush (either manual or powered) the corroded surface using a brass brush. Your local hardware store is a good source for simple brass brushes that are often used for cleaning spark plugs or jewelry. Rotary brass brushes for your Dremel or Proxxon are very suitable too. Never use steel brushes because they will ruin the surface of your gun including possible engravings. Don’t use a brush if your gun has a nickel finish: antique nickel layers are not very tightly bonded to the underlying iron.
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    Another way to get rid of rust is treating your gun with a chemical rust remover like Rustyco. If you let the corroded parts soak overnight in this solvent it even will remove rust from deep pitting. This method comes in very handy when rust has accumulated on parts of the frame that are not accessible. Beware: Rustyco may react aggressive on smaller cast iron parts or metals of poor quality when applied for days.
  • Elecrolytic removal of rust is a cheap, gentle and effective method which causes minimal damage to the metal surface. It’s quite easy to set up since all you need is a battery charger, a plastic or glass container (jar, bucket, bowl), some washing soda (sodium carbonate) and a strip of stainless steel.

Fill your container with a 1% solution of washing soda (10 grams/litre).
Make sure your battery charger is not connected to the mains.
Connect the negative lead (black) of your battery charger with the corroded gun part and connect the stainless steel strip with the positive lead (red).
Submerge your gun part in the solution and do the same with the stainless steel rod.
Make sure the stainless steel rod doesn’t touch the corroded gun part!
Connect your battery charger to the mains and switch it on.
Beware: a washing soda solution can irritate skin and eyes so always use plastic gloves and safety goggles!
Make sure no spills can reach your battery charger.
Do not use other salts (e.g. Table salt wich will generate toxic chlorine gas!).
Turn off the current when making adjustments to the setup.
Always work in a well ventilated environment since in this process generated hydrogen gas can form an explosive mixture with air when it's concentration in the air gets to high

  • Sandblasting with chalk is a method I haven’t tested yet. I sandblasted some rusted scrap iron using extremely fine sand but think it’s far to aggressive for use on antique firearms.